Climate change and dwindling water resources spur a broad research partnership to speed the development of drought-proof rice varieties for Africa. Producing just 1 kilogram of rice using traditional cultivation methods requires 2,500 liters of water — enough to fill a dozen oil drums. With the possibility of widespread drought in the coming decades because of climate change, will farmers be able to continue to grow rice the same way?
A major focus of the Benin-based Africa Rice Center (AfricaRice) is drought research. As almost 80% of Africa’s rice area is rainfed, drought is particularly devastating to the continent’s rice production.
Baboucarr Manneh, an AfricaRice biotechnologist deeply involved in drought research, points out that climate change is already being felt on the continent through droughts and floods that are more frequent and severe. One of the most viable options available to Manneh and his colleagues toward enabling farmers to adapt to climate change is to breed rice varieties with good drought tolerance.
“Fortunately, rice has a high level of genetic variation in traits related to drought tolerance, such as early maturity, deep root architecture and water-use efficiency,” Manneh says.
Studies by AfricaRice reveal that the indigenous African rice, Oryza glaberrima, is a striking example of drought tolerance, as it has the capacity to regenerate quickly when water becomes available again. O. glaberrima was domesticated in West Africa 3,500 years ago and is still grown in some areas.
Thanks to generous support from donors including the United Kingdom’s Department for International Development and the World Bank, seeds of these precious varieties have been preserved in the AfricaRice genebank and shared with researchers across the world.
This seed collection was key to AfricaRice’s development of new rices for Africa, abbreviated to NERICA, varieties that are crosses between African and Asian rice species. African rice farmers have shown particular interest in the early maturity of NERICA, which allows the crop to avoid drought in a short growing season.
AfricaRice and its partners use a three-pronged approach in their research on drought: (1) characterizing the drought profiles of rainfed rice production systems using geographic information systems and surveys; (2) adopting conventional breeding and marker-assisted selection to develop drought-tolerant rice; and (3) using integrated management options that adjust sowing dates, fertilizer regimes and sowing density to cope with drought.
Scientists have identified several traits that contribute to drought tolerance and rice breeding materials that possess those traits. Work is under way to identify molecular markers that tag genes that contribute to drought tolerance, thereby speeding breeders’ development of drought-tolerant lines.
Several partners are actively involved in this joint research, including, in addition to national programs, the International Rice Research Institute (IRRI), Japan International Research Center for Agricultural Sciences, Cornell University, and the International Center for Tropical Agriculture. Support comes from Japan, the Bill & Melinda Gates Foundation and the Generation Challenge Programme.
As part of this effort, the IRRI-AfricaRice project Stress-Tolerant Rice for Poor Farmers in Africa and South Asia (STRASA) works to accelerate the development and delivery of improved rice varieties that tolerate five major environmental stresses: drought, submergence, salinity, iron toxicity and low temperature. Funded by the Bill & Melinda Gates Foundation, STRASA is developing integrated management options that can mitigate the harmful effects of climate change in rice-based systems in these regions. Its overarching aim is to increase rice yields and the incomes of smallholder farmers.
Joining international researchers at IRRI and AfricaRice in STRASA are national agricultural research institutes, government extension systems and civil society groups in 17 countries. Active STRASA countries in Africa include Benin, Burkina Faso, The Gambia, Ghana, Guinea, Mali, Nigeria and Senegal in West Africa, and Ethiopia, Madagascar, Mozambique, Rwanda, Tanzania and Uganda in eastern and southern Africa.
The achievements of the project include the development of promising stress-tolerant breeding lines, the training of national scientists, technicians and farmers in modern breeding approaches, improved seed production and impact assessment and the production of seed of stress-tolerant varieties. The project has successfully established improved and standardized screening facilities for the different rice stresses and enhanced research capacities of national partners.
Local scientists and farmers are collaborating in the field-testing and dissemination of the new stress-tolerant varieties in various African countries. This concerted effort to develop and deliver stress-tolerant rice is expected to have widespread application and impact in rainfed systems across Africa.